Nesteto finally told you where Bollvig is. Fly to the Floating Island and talk with Bollvig.
Step 1. Talk with BollvigAn Asmodian who came to Elysea to slaughter the Elyos, but found only tragedy He resides in the The Storm Circle..
Step 2. Report the result to BetoniA ghost near the Hoarfrost Shelter in Beluslan. He failed in his duty to protect the Observatory..